Feature: Dynamic Icons for File Groups

[z8dn]

Description

Allow users to customize icons for specific file patterns or groups. Currently, icons are automatically matched, but providing manual overrides or custom icon selection would improve visual navigation.

Expected Use Case

A user has a group called 'Infrastructure' with various config files. They might want to assign a 'Cloud' or 'Settings' icon to this specific group to make it stand out in the project tree regardless of the file types inside.

What it should look like

When editing a file group in the 'Edit File Group' dialog, there would be an icon picker or a way to specify an icon name from the IntelliJ platform's icon set.